honestly if we have a GDL redux series, i'd put it during the Black out. you could have Alex's kid or grandkid* starting up a unit during the chaos that is the blackout and resulting conflicts. perhaps with a name that homages the GDL without being just the GDL take II. (perhaps the kid grew up with tales of his grandfather Greyson?) the low intensity conflicts early in the blackout would be a perfect place to use some of the tropes from the early GDL books in new ways, and then once the unit is larger and more established, you can toss them into the mess that is the Wolf Relocation and Falcon Desant.
*the ambiguity over Alex's fate works well here.. could even be left unanswered. even if he died on tharkad in the early jihad, there was enough time for him to have had a kid before then. and he might well have been offworld when that happened.